NASA engineers experimenting with additive manufacturing have took their efforts to the next level earlier this week by 3D-printing the first-ever, full-scale copper rocket engine part.
According to the US space agency, the component that was produced is a combustion chamber liner capable of operating in extreme temperatures and pressures, and the process used to make it has the potential to drastically reduce the time and money needed to manufacture rocket parts.
Steve Jurczyk, associate administrator for the Space Technology Mission Directorate at NASA Headquarters in Washington, called it “a milestone for aerospace 3D printing,” adding, “additive manufacturing is one of many technologies we are embracing to help us continue our journey to Mars and even sustain explorers living on the Red Planet.”
A challenge to the additive manufacturing team
Engineers verified that the part was built as designed by using structured light scanning on a computer screen, and they noted that it will be used in a rocket combustion chamber, where the super-cold propellants used to help provide thrust are mixed and heated to extreme temperatures. It is one of many highly-complex components needed to send rockets into space.
“On the inside of the paper-edge-thin copper liner wall, temperatures soar to over 5,000 degrees Fahrenheit, and we have to keep it from melting by recirculating gases cooled to less than 100 degrees above absolute zero on the other side of the wall,” explained Chris Singer, director of the Engineering Directorate at NASA’s Marshall Space Flight Center in Huntsville, Alabama, where the copper rocket engine liner was manufactured.
“To circulate the gas, the combustion chamber liner has more than 200 intricate channels built between the inner and outer liner wall,” Singer added. “Making these tiny passages with complex internal geometries challenged our additive manufacturing team.”
Members of Marshall’s Materials and Processing Lab used a selective laser melting machine to fuse 8,255 layers of copper powder to create the chamber, a process which took 10 days and 18 hours to complete. Prior to making the liner, materials engineers created several other test parts, characterized the material and developed a process for 3D printing using copper.
Working to create cheaper, more affordable rocket engines
Materials engineer Zach Jones explained that copper “is extremely good at conducting heat. That’s why copper is an ideal material for lining an engine combustion chamber and for other parts as well, but this property makes the additive manufacturing of copper challenging because the laser has difficulty continuously melting the copper powder.”
Thus far, only a handful of copper rocket parts have been made using 3D printing, meaning that the agency is blazing new trails by using additive manufacturing to produce a rocket part that has to be able to withstand both extreme hot and cold temperatures, as well as have complex cooling channels built on the outside of an inner wall that is as thin as a pencil mark.
The rocket part was built using a copper alloy known as GRCo-84, which was created by NASA materials scientists at the Glenn Research Center in Cleveland, Ohio. Researchers at that facility have conducted extensive materials characterization that helped validate the 3D printing process parameters and ensure the quality of the build, the agency said, and will also develop a database that will be used to guide future 3-D printed rocket engine designs.
“Our goal is to build rocket engine parts up to 10 times faster and reduce cost by more than 50 percent,” said Marshall propulsion engineer and project leader Chris Protz. “We are not trying to just make and test one part. We are developing a repeatable process that industry can adopt to manufacture engine parts with advanced designs. The ultimate goal is to make building rocket engines more affordable for everyone.”
For more on NASA 3D printing, and its future implications, read our exclusive interview with Niki Werkheiser, NASA 3D printing in zero G project manager.